Blood test boosts colorectal cancer chemotherapy precision: Study

An Australian trial using circulating tumour DNA (ctDNA) blood tests to guide colon cancer treatment has found outcomes are as good as standard practice, but with the benefit of allowing many patients to avoid chemotherapy.
 
The Peter MacCallum Cancer Centre’s Australian DYNAMIC trial involves 455 patients with stage two colon cancer who first had surgery to remove their cancer.
 
Patients were then randomised into two groups, with one having their need for follow-up chemotherapy determined by the liquid biopsy blood test, while in the second group, the standard criteria determined who would have chemotherapy.
 
While standard criteria recommended follow-up chemotherapy for 28% of patients, the ctDNA pathway recommended 15% needed chemotherapy.
 
Publishing its five-year results this month, researchers found the five-year overall survival was 93.8% in the ctDNA-guided group compared to 93.3% for the standard management group, and that recurrence-free survival, no return of cancer over five years, was 88% versus 87%, respectively.
 
The study concluded that the approach can decrease the number of people needing chemotherapy, without compromising their outcomes.
 
Professor Jeanne Tie, lead study investigator and lower GI medical oncologist, said GPs could play an important role in supporting patients through explaining and understanding the tests in the future.
 
‘People love their GP … they often go back to the GP to get their opinion about something,’ she told newsGP.
 
‘It’s important to know that if someone has a positive test, if they don’t have any further treatment, the risk of cancer coming back is extremely high.
 
Professor Tie said additional research results, covering stage three colorectal cancer, are expected later this year, which together with the current results, will cover more than 50% of people with the cancer.
 
She hopes that, in time and if survival benefits are proven, the tests may offer real time monitoring of cancer.
 
‘This is like a microscopic way of tracking these cancers in the sub-imaging level to see whether the treatment has worked or not … and hopefully that will improve survival,’ Professor Tie said.
 
‘A new test is great, but you have to always think about, what if you find the result which is not what they want to hear? Is it going to cause more harm?’
 
Moving forward, the researchers say other benefits of ctDNA testing may include testing at the end of treatment to gauge how well they had worked and stratifying longer term risks of cancer recurrence.
 
Similar tests may also play a role in cancer screening, with some pathology companies offering private ctDNA tests for lung cancer, colorectal cancer and melanoma.
 
However, Professor Tie urged caution and says more research is still needed into the use of blood tests in cancer screening,
 
‘The question really is, with detecting early, does it change outcomes?’ she said.
 
Log in below to join the conversation.

blood test bowel cancer cancer colon cancer